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Ecosse L. Lamoureux, Aron Murphy, Anthony Sparrow, and Robert U. Newton

This study examined the effects of improved strength on an obstacle course (OC) simulating gait tasks commonly encountered by community-living older adults. Forty-five adults (mean age 68.2 ± 1.5 years) were randomly assigned to a control (10 women, 5 men) or an experimental group (EXP; 19 women, 10 men) and trained 3 days/week for 12 weeks. Using a 1-repetition-maximum (1-RM) method, 6 leg-strength measures were evaluated pre- and posttest. The times to walk an OC of 4 gait tasks (stepping over and across an obstacle, negotiating a raised surface, and foot targeting) set at 3 progressively challenging levels were also assessed. Significant Group × Time interactions were found on all 1-RM tests, with only EXP recording significant improvements (124–147%; p < .001). Strength gains in EXP were accompanied by significant improvements in the times to negotiate all gait stations and walk the entire OC (6-15%; p = .001–.014). This study showed that improving strength is an effective strategy to improve community locomotion, which might decrease the risks of falls in community-living older adults.

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Daniel A. Galvão, Robert U. Newton, and Dennis R. Taaffe

Resistance training has been shown to be the most effective exercise mode to induce anabolic adaptations in older men and women. Advances in imaging techniques and histochemistry have increased the ability to detect such changes, confirming the high level of adaptability that remains in aging skeletal muscle. This brief review presents a summary of the resistance-training studies that directly compare chronic anabolic responses to training in older (>60 years) men and women. Sixteen studies are summarized, most of which indicate similar relative anabolic responses between older men and women after resistance training. Relatively small sample sizes in most of the interventions limited their ability to detect significant sex differences and should be considered when interpreting these studies. Future research should incorporate larger sample sizes with multiple measurement time points for anabolic responses.

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Michael R.M. McGuigan, Roger Bronks, Robert U. Newton, John C. Graham, and David V. Cody

Peripheral arterial disease (PAD) is associated with impaired lower extremity function. This study investigated differences in PAD and control participants and the relationship between lower limb strength and clinical measures of PAD severity. Participants were evaluated by 6-min-walk distance, normal and maximal walking speed over 10 m, isometric plantar-flexion strength, and dynamic dorsi-/plantar-flexion strength. Hemodynamic measures of the lower limbs were recorded at rest and after maximal treadmill testing. PAD participants walked significantly less far during the 6-min walk, and there were large differences in normal and maximal walking speeds. Small to moderate differences were found for isometric plantar-flexion strength. In the diseased legs of the PAD participants, resting systolic hallux photoplethysmography was significantly correlated with isokinetic plantar-flexion strength and onset of claudication pain during the 6-min-walk test. In addition to confirming the documented loss of walking endurance, these data suggest that loss of strength of the plantar flexors is associated with increasing PAD impairment.

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Rajni Rai, Michelle I. Jongenelis, Ben Jackson, Robert U. Newton, and Simone Pettigrew

According to ecological models of behavior, the physical environment can influence physical activity engagement by a series of mediating and moderating processes. This study tested such a model to identify factors relevant to older adults’ engagement in moderate–vigorous physical activity. Sociodemographic, psychological, physical, and environmental factors were assessed in 432 Western Australians aged 60 and older. Moderate–vigorous physical activity was measured objectively using accelerometers. No environmental variables were related to engagement in moderate–vigorous physical activity either directly or indirectly. However, various individual-level factors were significant, indicating that these may be more important than environmental factors in locations such as Australia that have generally conducive environments and ambient conditions.

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Rajni Rai, Michelle I. Jongenelis, Ben Jackson, Robert U. Newton, and Simone Pettigrew

Retirement has been identified as a life transition that is important in determining older adults’ physical activity levels. The present study examined the factors associated with retirement that affect physical activity participation among older adults. Semistructured interviews were conducted with 425 retired Australians aged 60 years and older. Physical activity was assessed objectively, using accelerometers. Two categories of factors affecting physical activity participation following retirement were identified: the various physical and psychological changes in later life that can encourage or discourage physical activity and the adaptation processes undertaken by older people in response to these changes. The adoption of either a gain or loss approach to retirement and aging appeared to be the most influential adaptation factor affecting physical activity participation. The results suggest that intervention approaches should aim to foster more positive attitudes to aging and retirement and promote physical activity at all stages in life.

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Keijo Häkkinen, Markku Alen, Mauri Kallinen, Mikel Izquierdo, Kirsi Jokelainen, Helka Lassila, Esko Mälkiä, William J. Kraemer, and Robert U. Newton

Forty-two healthy men and women in two age groups (40 and 70 years) were examined for muscle cross-sectional area (CSA), maximal voluntary bilateral isometric force, force-time characteristics, maximal concentric 1 RM. and power performance of the leg extensors in a sitting position, squat jump, and standing long-jump. The results suggested that the decline in maximal strength with increasing age is related to the decline in muscle CSA; however, particularly in older women, the force/CSA ratio may also be lowered. Explosive force seems to decrease with increasing age even more than maximal strength. suggesting that muscle atrophy with aging is greater in fast-twitch fibers. The voluntary activation of the agonist and antagonist muscles seems to vary depending on the type of muscle action and/or velocity and time duration of the action in both age groups but to a greater extent in older people. There appears to be an age-related increase in antagonist co activation. especially in dynamic explosive movements.